Here's a quick update on the position with upgrading MediaWiki. You may remember that when we tried to go to the latest version of MediaWiki there was a drastic slowdown across all Wikia hosted wikis. It's taken quite a while to pin-point exactly why this happened. It didn't happen to Wikipedia, so it wasn't clear why we were having this problem (most people are not on 1.7alpha, which is ahead of the main release, so not a lot of info on other's experiences with this version).
So John and Jason have been carefully testing various versions in an attempt to isolate which exactly which change was causing the slowdown. There were a lot of changes in between, so finding the problem change wasn't simple. They have now isolated it, fixed it, and hopefully we are ready to go to 1.7Alpha r15298 - not far off the version that Wikipedia is on at the moment. That's being tried on Monday.
There have been a few tests over the last couple of weeks, some of which have caused some slowdown or broken html tags. So many thanks to everyone for your patience with this. Hopefully this upgrade will bring in some features that we've been waiting for (I hardly dare say it but... fully working parser functions?)
After this, the plan is to go to a more regular upgrade schedule. That will mean much smaller, and so safer, jumps between versions.